TIL that's good to know, thanks !
Yeah I might end up doing that ; I'm still hoping to find a good compromise built out of Lego, since it's easy to reuse the bricks for whatever other project later on.
Do you know of any example of ballasting R56 with Lego, maybe with another brand than Trixbrix, that I could use for inspiration, but with a "1 piece" curve track ? (I mean Not like L-Gauge reference instructions for R56 which uses 2-pieces ME Models rails the actual curve : http://l-gauge.org/downloads/Ref006BallastR56CurveRevA.pdf).